If pain that a test subject has can be measured and objectively shown, it is possible to objectively measure the efficacy of a pain killer or visualize the pain of the test subject for an adequate medical treatment. Conventionally, as disclosed in, for example, Patent Document 1, a method of quantifying pain is used where the scale indicating the degree of pain is handed to a patient, the patient moves the cursor based on the degree of his or her pain, and the degree is read.    Patent Document 1: U.S. Pat. No. 6,258,042